Let's go through these:
-timing belt - Are you talking about a timing chain?? I don't know what the deal there is. You'd have to explain why it "needed" replacing in order to comment. Normally it lasts the life of the engine. But perhaps there was a specific reason like a damaged chain guide, etc.
-tpms sensor - Tire pressure sensors can fail. The batteries can leak juice. Sometimes they are bad out of the box. Under the best circumstances, you might get maybe 10 yrs. That's the age of your truck. Sometimes it can be trauma too. A tire tech can mistakenly bump them in the process of replacing tires. I don't want to be conspiratorial ...but I've changed a lot of tires and know it doesn't take much to crack one. Easier than you think. A tech probably isn't going to say, "Gee wizzz, mr customer, I'm underpaid and overworked, but let me buy a new $60 sensor out of my own pocket for you ...and I just won't buy new shoes for my crippled kid." Nope. "Um, mr customer, we noticed you have a bad tire pressure sensor ...we think it would be prudent to replace it." But in your case it was probably just age or bad battery. I wish they'd stop using those stupid TPMS systems anyway.. (sorry that's just me).
-two o2 sensors - These shouldn't go out in the age of your truck. It either points to something like an internal coolant leak that killed them, a prematurely failed (faulty) part, or a wild guess by a tech to resolve another operational issue. Sometimes you try various things to resolve an engine condition and you get to the end of the line ....and then it makes sense to throw a few (strategic) parts at a problem (considering labor costs). Maybe the mounts were cracked and 'spoofed' bad O2 sensors. W/o knowing the EXACT situation from the mechanic's perspective, nobody can really say.
-water pump - Water pumps are one of those things which may last 200k miles, or 30k miles (or can fail after 500 miles). Usually somewhere in between and hopefully at the long end of the spectrum. Bearings, seals etc can fail, some sooner than others. That's just manufacturing probability. So you didn't get to the high end of the spectrum on that one.
-serpentine belt - Same as above ...they only last so long. The cost of NOT replacing can be way more than doing so. Wear item.
-MAP sensor - Maybe the one you had in there before could have been cleaned. Some may last the life of your truck, others may not. How often was the air filter replaced? Was it an aftermarket (oil impregnated) filter? Those are known to kill MAP sensors. Maybe a real dusty envrionment? Maybe a tech just taking a swing at problems and said it was bad (when it wasn't)? Or maybe a failed part.
-all four tires - Tires wear out. How often were they rotated? Was the air pressure too high/low? Worn suspension parts? Too fast around corners?? Damaged chords? Terrible balance job when new?
And still have to fix:
-crack in one o2 sensor mount - Could have been damaged during factory install, terrible weld when new, Cracked due to 20,000 heat/cool cycles, or who knows? Shouldn't happen, but I give the mechanic credit for finding the crack. That's tricky to spot.
-bad U-joints in the front driveshaft - These wear out. I'd say it was premature for your truck's mileage. But does it see a lot of water? Did the previous owner off-road it? Probably shouldn't happen with the miles your truck has, but it's an easy fix. Lot less expensive than the other end of the driveshaft. Might want to check the rear U-joint too while you're at it.
It's frustrating ...but look on the good side, what are the things which COULD have failed but haven't: Trailer brake controller, P/S pump, A/C compressor, Heater core, HVAC damper door motors, TIPM (ECU) fuel pump rely, TIPM corroded connectors, Fuel pump, Fuel pump pressure regulator, Battery, Corroded battery cables, TIPM, Leaking shocks, Rear 3rd light water leak, ABS brake module, Wheel bearing/hubs, Driveshaft center bearing, Transmission shift solenoids, Leaky pinion seals, Rear wheel bearings, P/W switches, Column shifter break, U-connect issues, Upper control arms, anti-sway bar crack, Sway bar end-links break, Stuck thermostat, Major body rust, failed brake pedal switch, worn/torn driver's side seat cushion, Airbag light on, intake leak, exhaust manifold warpage, wiped out cam (5.7's), ruined engine (5.7's), brake wheel sensor fail, Rodents chewing wires, Birds stealing wiper arms! ..Starter, Alternator .....guys help me fill in what I've left out (my fingers are getting tired!!)....
I'll spare making a list of all the things I've had to replace on my H3!! Long list and they're all big items. I sill love that vehicle though
But I get it. You're frustrated with the costs. You're venting. I understand and I DO sincerely sympathize with you. I don't like it either when things fail. It sucks. We all wish for a vehicle that'll go 150k w/o much trouble. Sometimes they do, sometimes not. Should you keep or sell? Who knows? Hopefully with the items you've replaced so far, it'll be smooth sailing for a while, but OTOH, as a vehicle ages and parts wear, statistics say it's more likely things/parts will fail. If you buy new you get a warranty and shield yourself from costs for a while. That's the price of buying new.